With the rapid development of the display technology, a technology of narrow bezel and wide viewing angle has become the mainstream development trend of the display panel. The technology of narrow bezel and wide viewing angle can bring a better visual experience to an user. In a structure of a current electronic device, an LED (Light Emitting Diode) that is used as a light source is a point light source, and a light mixing distance between the LEDs is relatively long, at least more than 2.5 mm, which cause a light incident distance of a backlight module being more than 2.8 mm, thus hampering the maximization of a viewable region of the electronic device, and limiting the development of narrow bezel technology.